The Department of Pediatrics, Baylor College of Medicine, has participated in cooperative cancer study group activities (Southwest Cancer Chemotherapy Study Group, Southwest Oncology Group, Pediatric Oncology Group) for 25 years. The purpose of each group has been to search for better methods of treatment by which to cure or control cancer in children. As a result of these activities, more than half of the children with cancer will survive their disease. In the evolutionary development of these groups, increasing emphasis has been placed upon coordinating multidisciplinary care and on expanding knowledge of cancer biology and pathophysiology. Essential information on the natural history of specific disease entities has provided important knowledge of prognostic factors that are critical elements of modern experimental design. Biostatistical involvement has become an essential part of the integrated programs that now include equal participation by the medical oncology, surgery, pathology, and radiotherapy disciplines. This project will continue this highly successful process.